Heating apparatus



Sept. 13, 1949. M, L. MUELLER HEATING APPARATUS 2 Sheets-Sheet l IN VEN TOR. Marl ZZ A Mueller rroR/VEX Filed April 18, 1945 %ALWY Sept. 13, 1949. M. MUEYLLER 2,481,861

EATING APPARATUS Filed April 18, 1945 v 2 Sheets-Sheet 2 WMWWWMWN /7 IN VEN TOR. K wail A. M21624 Patented Sept. 13, 1949 UNITED STATES PATENT OFFICE HEATING APPARATUS Moritz L. Mueller, Columbus, Ohio Application April 18, 1945, Serial No. 588,933

3 Claims. 1

This invention relates to heating apparatus and. has particular reference to a heating system of the chimney furnace type as disclosed and claimed in my Patents No. 2,274,341, issued February 24, 1942, and Nos. 2,348,834 and 2,348,835, issued May 16, 1944. In fact, the present invention comprises an improvement upon the constructions as disclosed in said patents and has particular reference to a novel and extremely useful improvement in the construction for the heat exchanger part of the system. The present invention contemplates a construction for the heat exchanger which is calculated to increase the efficiency of the system and also to simplify the shipment of the parts therefor when in a knockdown condition.

Principal objects of the invention are to provide:

A new and efiicient construction for a heating system of the chimney furnace type;

A new and improved construction for the heat exchanger thereof which is designed to increase the efiiciency of the system;

A new and improved construction for the heat exchanger part of the system which is calculated to simplify and reduce the cost of shipping the parts thereof in a knockdown condition.

Other and further objects of the invention will be apparent from the following description and claims and will be understood by reference to the accompanying drawings, of which there are two sheets, which, by way of illustration, show preferred embodiments and the principles thereof and what I now consider to be the best mode in which I have contemplated applying those principles. Other embodiments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention and the purview of the appended claims. I also contemplate that of the several different features of my invention, certain ones thereof may be advantageously employed in some applications separate and apart from the remainder of the features.

In the drawings Fig. 1 is a fragmentary, somewhat diagrammatic view, with certain parts shown in section, and illustrating one form of the invention;

Fig. 2 is a sectional view of a nested stack of parts as they may be assembled for shipping purposes and which form a part of the heat exchanger of the system;

Fig. 3 is a fragmentary View, partially in section, of a modified form of the invention Fig. 4 is an enlarged fragmentary sectional view of the damper and control arrangement of the modification illustrated in Fig. 3; and

Figs. 5 and 6 are plan views of the lower and upper parts, respectively, of the damper and control arrangement illustrated in Fig. 4.

Referring now to Fig. 1, there are illustrated fragmentary parts of a house which include space ill to be heated forming part of the dwelling which includes a floor I2, a ceiling I4, attic space It, and a roof [8. A masonry chimney 20 extends upright to and above the roof of the building and has an atmospheric discharge for the products of combustion. The fuel burning means, in the present instance an atomizing type of oil burner 22, is operatively associated with a combustion chamber 24 formed in the lower part of the chimney 2B. Controls for regulating and controlling the operation of the fuel burning means 22 according to any of the suitable arrangements as disclosed in my Patent No. 2,348,834 may be employed, or any other desired control arrangement may be employed so as to regulate the operation of the fuel burning means 22 so as to supply heat as desired to the space [0.

The interior of the chimney is divided into an air path 26 for the air to be heated and a combustion products path 28 for the flue gases, in the present arrangement the air path surrounding the combustion products path 28. The paths 2% and 28 are defined by the chimney 20 and a tubular heat exchanger 30 which is arranged within the chimney 20 and spaced from the walls thereof. The lower end of the heat exchanger 30 is connected to a combustion chamber 24 so as to receive the heated products of combustion and may, as illustrated, be seated upon the upper rim of the walls which define the combustion chamber 2G. The heat exchanger 30 extends vertically throughout the major portion of the length of the chimney 20 in spaced relation with the side walls thereof, preferably so as to define annular air path 26.

The upper end of the air path 26 is closed by a partition 32 which extends across the interior of the chimney 20 and is provided with a suitable opening through which the heat exchanger 38 extends. The partition 32 cooperates with the heat exchanger 30 to separate the air path 26 from the flue path 28. The heat exchanger 30 may terminate below the top of the chimney 20. The upper end of the air path 26 is provided with an air inlet openin 34 through which an electric motor operated blower 35 supplies air to the upper end of the air path 26 and under pressure so as to cause such air to flow downwardly through the air path 26 and over the surface of the heat exchanger 36. The air may be delivered through the opening 34 at one side of the heat exchanger 30 so that the air will tend to flow in a spiral downwardly through the path 26, thereby effectively absorbing heat from all surfaces of the heat exchanger 30.

The lower end of the air path is provided with an outlet 36 which communicates with a duct 38 which in turn communicates through branch ducts with warm air outlets, such as 40, discharging heated air into the space ID. The air inlet to the blower 36 is connected through suitable ducts 42, M and 46 to return air outlets, such as 43, from the space ID to be heated so as to permit the recirculation of air from the space in through the heating system and ducts associated therewith for reheating the same in order to heat the space l6 to the desired extent.

The blower 36 is adapted to be operated automatically with reference to the temperature of the flue gases in the flue gas path 28, or the operation of the fuel burning means 22 so as to circulate air through the air path 26 in order to recover the useful heat from such flue gases.

In my aforesaid earlier patents, as well as in my Patents No. 2,361,643 and No. 2,361,644, issued October 31, 1944, there are shown several different control arrangements for regulating the operation of the blower, any one of which or any other desired arrangement may 'be .employed.

The height of the chimney and the size of the flue path 28 are such as to produce a high potential draft through the combustion chamber 24 and the efiicient combustion of fuel therein. It is to be understoood that the pressure of the air in the air path 26during theroperation of the blower is greater than that of the .fiue gases in the path '28 so that if any leakage of the heat exchanger 30 should occur, such leakage will be of air into the flue path 28 and not vice versa, thereby avoiding contamination of the air path 26.

The heat exchanger 30, as illustrated, comprises a series of frusto-conical pipes D, 51, 52, 53, 54, and 55 stacked one upon the other with the bottom edge of the upper one overlapping the upper edge of. the lower one so as to produce an effective seal at each joint. It will thus be ob served that the walls of the heat exchanger 30 slope inwardly slightly so as to obtain impingement of the flue gases on the walls of the heat exchanger 36. It will also be observed that the walls of the heat exchanger 36 taper outwardly from the inlet to the outlet of the air path 26 so as to provide good contact and wiping action between the air as it circulates through the path 26 and the outer tapered surface of the heat exchanger 30.

The pipe sections 50, 5|, 52, 53, 54, and 55 may also be made of different gauge metal so that the lower sections 50, 5|, etc., are of heavier gauge than the upper sections, the thickness of the gauge decreasing with the distance from the combustion chamber 24. The thickness of the pipe sections has been somewhat exaggerated in the drawings, but I have found that a variation in gauge of an 8-.gauge black iron tapered metal pipe for the lower section 50 to a 22-gauge galvanized iron pipe for the section 55 may be employed. The variation in gauge, of course, will depend to some extent upon the length of the heat exchanger 33 and the capacity of the system.

In so far as the galvanized iron pipe is concerned, I have discovered that the porcelaincoated pipe of this character now availabe commercially is quite suitable for use as part of the heat exchanger, particularly for the upper portions thereof. Thus, with the tapered tubular heat exchanger, the hot flue gases rising upwardly in the air path 28 and the down-flowing air in the path 26 will better wipe the surfaces of the exchanger 30, thereby more efficiently transferring heat therebetween.

In order further to promote the exchange of heat between the flue gases in the path 28 and the air in the path 26, a hollow pipe 69 closed at its ends may be arranged centrally of the heat exchanger 3.0 so as to force the flue gases flowing upwardly in the path 28 into good contact with the inner wall of the heat exchanger 3!].

As furnaces of this type are not preassembled but the parts thereof are made and shipped to each particular job and there assembled during the building of the chimney 20, the matter of shipping the parts economically is an important factor. I have found that the tapered pipe sections may, in their disassembled or knockdown condition, be nested in the manner illustrated in Fig. 2 so as to provide an assembly of the heat exchanger for shipping which is compact and only a very small portion of the length of the heat exchanger in its form when assembled. Due to the tapered nature of the pipe sections, each one thereof may be nested at least to a certain extent in the one therebelow, and in this manner the entire heat exchanger in its knockdown condition need for shipping purposes only to displace slightly more space than the longest one of the sections. This not only contributes to saving in the matter of freight rates and packaging, but also makes it possible to conveniently assemble for each particular job in one convenient package all of the elements of the heat exchange section.

In the embodiment of the invention illustrated in Figures 4, 5 and 6, which is a modification of that disclosed in Figs. 1, 2 and 3, the feature of the tapered frusto-conical heat exchanger has been retained in a modified form and the hollow pipe 60 in the previous embodiment has been utilized as the flue for a water heating system which is operatively associated with the chimney furnace in Figs. 3 to 6. In this modification, while the construction of the heat exchanger I30 is different insome respects from that illustrated in Fig. 1, the same action is obtained although the two lower sections I50 and 'I5I of the heat exchanger may be cylindrical in form. In this case, the pipe I60 which has the same function as the pipe 60 in the previous modification, is enlarged at its lower end I6I to provide a chamber in which a water heating coil I62 is arranged, such coil being operatively associated with a hot water storage tank I63 of a hot water system of a dwelling for heating water and storing the same in such tank 163. The enlarged end |6I which forms the chamber for the water heating coil is in the form of a pipe, the lower end of which has a damper and control arrangement as illustrated in Fig. .4.

A stationary valve member I65 .is arranged in the form of a cap .and seated upon the upper .end of the lower section I 50 of the heat exchanger I30, The valve member I65 is provided with two series of openings I 6! and 159 as illustrated in Fig. 5, the series I61 comprising a number of holes arranged in .an annular row adjacent the outer periphery of the valve member I65, while the series I69 comprises a series of holes'arranged in a circle within the series I61. The upper valve member I68, as illustrated in Fig. 6, rests upon the lower valve member I65 and is rotatable thereon so as to align the openings I10 in the valve member I68 with either the series of openings I61 or the series of openings I69.

It will be observed that the pipe section I6I which forms the chamber for the water heating coil is of materially less diameter than the outer pipe section II which forms a part of the heat exchanger. The series of openings I66 register with the interior of the pipe I6I so that when the openings I10 are aligned with the openings I69, flue gases from the combustion chamber I24 pass upwardly through the pipe section I50 and thence through the openings I69 into the interior of the chamber in which the water heating coil is arranged for heating such coil, and thence upwardly through the flue I60 thereabove.

When the upper damper or valve I66 is set so that the openings I10 therein are aligned with the series of openings I61, the flue gases, instead of passing upwardly over the water heating coil, will pass through the space between the pipe sections I6I and I5I, thereby by-passing or shunting the water heating coil out of the path of the flue gases. The upper damper I66 may be set so as to align the openings therein with either of the series of openings in the lower damper I65, or so as to partially expose both of said series of openings so as to permit the flow of flue gases not only through the water heating chamber but also directly through the flue path I26 between the pipe I60 and the heat exchanger I30.

When the damper control is arranged so that all or substantially all of the flue gases pass upwardly through the water heating chamber, there may not be much heat which can be recovered by the air flowing through the air path I26 in view of the absorption of heat by the water heating coil I62 and also due to the fact that the flue gases are flowing upwardly through the pipe I60. While the blower I36 may be allowed to operate at such time, particularly during the heating season of the year, it may be desirable when the chimney furnace is operated solely for heating water, such for example as during the summertime, to discontinue the operation of the blower I36 and to this end the circuit for-the electric motor which drives the blower I36 may be provided with a manually operable cutout switch, such as illustrated in Fig. 3 of my Patent No. 2,348,835, the blower being normally automatically operable as previously described to circulate air through the air path I26 so as to recover heat from the flue gases. However, if the electric motor circuit is manually opened as just described, heat to an undesirable extent may accumulate in the heat exchanger I30 and in order to dissipate this heat without introducing it into the space to be heated, I have provided a thermostatically controlled damper I10 which controls a relief vent by-pass I12 between the air path I26 and the flue path I28 which leads to atmosphere through the opening in the top of the chimney.

This thermostatically controlled damper I10, which is illustrated largely diagrammatically, may be of the construction and operation according to the disclosure as shown in my Patent No. 2,348,835 and particularly in Figs, 4, 5 and 6 thereof. Generally speaking, the damper I10 is adapted to be opened so as to open the by-pass when the temperature of the air at the upper end of the air path I26 reaches a predetermined degree (preferably higher than that at which the thermostatic switch for the motor circuit is set to close), as will happen when the operation of the blower I36 is cut out by opening of the manual switch.

The damper I10 is mounted upon a horizontal pivot I14 and when closed as illustrated in Fig. 3 is adapted to close the by-pass I12. However, when open it permits the by-pass I12 to vent the upper end of the air path I26 to atmosphere. To permit the thermosiphonic flow of air through the air path I26 at such time, the lower end of the air path may be provided with an opening I16 normally closed by a pivoted damper I18 and which is arranged to be operated by the control I which shifts the damper I68 so that when the damper I68 is set to supply the flue gases to the water heating coil chamber, the damper I16 will be open. The damper I18 may also be arranged to be operated independently of the damper control I80.

The damper control I80 comprises a rod which may project from the chimney and have its inner end connected to the damper member I68 for shifting the same between its two positions in order to selectively control the amount of heat absorbed by the water heating coil I62.

While I have illustrated and described a preferred embodiment of my invention, it is to be understood that this is capable of modification and I therefore do not wish to be limited to the precise details set forth, but desire to avail myself of such changes and alterations which may fall within the purview of the following claims.

I claim: 7

1. Heating apparatus comprising an upright chimney having an atmospheric vent at the upper end thereof, and a combustion chamber at the bottom thereof, fuel burning means associated with said combustion chamber, a tubular heat exchanger connected at its lower end to said combustion chamber to receive heated products of combustion therefrom and extending upwardly through said chimney for a major portion of the length thereof and in spaced relation with the inner walls of said chimney, said heat exchanger cooperating with said chimney to provide a flue passageway and an air passageway in intimate heat exchange relationship with each other through said heat exchanger, a blower arranged for introducing air to be heated under pressure into the upper end of said air passageway and forcing such air downwardly through said air passageway in countercurrent heat exchange relationship with said flue gases, said air passageway having an outlet for heated air at its lower end, a tubular member arranged in said flue passageway in spaced relationship with said heat exchanger and for a substantial portion of the length thereof, a water heating unit disposed in a lower portion of said tubular member, and a damper arranged at the lower end of said tubular member and constructed and arranged to direct said flue gases across said heating unit and through said tubular member in one position of said damper and to direct said flue gases around said heating unit and through said heat exchanger in another position thereof.

2. Heating apparatus comprising an upright chimney having an atmospheric vent at the upper end thereof, and a combustion chamber at the bottom thereof, fuel burning means associated with said combustion chamber, a tapered tubular heat exchanger connected at its lower end to said combustion chamber to receive heated products of combustion therefrom and extending upwardly through said chimney for a major portion of the length thereof and in spaced relation with the inner wallsof said chimney, said heat exchanger cooperating with said chimney to provide a fine passageway and an air passageway in intimate heat exchange relationship with each other through said heat exchanger, a blower arranged .for introducing air to be heated under pressure into the upper ,end of said air passageway and forcing such air downwardly through said air passageway in countercurrent heat exchange relationship with said fiue gases, said air passageway having the outlet for heated air at its lower end, said heat exchanger tapering inwardly in the direction of flow of flue gases and outwardlyin the direction of said flow of air, a tubular member arranged in said flue passageway in spaced relationship with said heat exchanger and for .a substantial portion of the length thereof, a water heating unit arranged in said tubular member, and .a damper arranged at the lower end of said tubular member and constructed and arranged to direct said flue gases throughsaid tubular member in one position of said damper and to direct said flue gases through said heat exchanger in another position thereof.

3. Heating apparatus comprising an upright chimney having an atmospheric vent at the upper end thereof, and a combustion chamber at the bottom thereof, =fuel burning means associated with said combustion chamber, a tapered tubular heat exchanger connected at its lower end to said combustion chamber to receive heated products of combustion therefrom and extending-upwardly through said chimney for a major portion of the-length thereof and in spaced relation with the inner wallsof said chimney, said heat exchanger comprising a stack of nestable ,frusto-conical pipe sections which cooperate with said chimney to provide a flue passageway and 8?. a ai pa sa ewa nii tigia il bexch s lationship with,each otherathrough said heat excha e -.mem ai nss ab i sections ing a relation between the 1ength, s1ope and wall thickness thereof such that sections of the same length will stack tightly within one another in the reverse order of their assembly in said apparatus and within the overall length of one of said sections, a blower arranged for introducing air to be heated under pressure into the upper end of said air passageway and forcing such air downwardly through said air passageway in countercurrent heat ,exchange relationship with said flue gases, said air passageway having its outlet for heated air at its lower end, said heat exchanger tapering inwardly in the direction of flow ,of flue gases and outwardly .in the direction of .said flow of ,air.

.MORITZ L. MUELLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 563,368 Frost July 7, 1896 780,587 Vanderhoof Jan. 24, 1905 835,810 Collins Nov. 13, 1906 1,575,056 Johnson Mar. 2, 1926 1,983,843 Eisinga Dec. ,11, 1934 2,156,101 Willett et a1. Apr. 25, 1939 2,201,312 'Hauser May 21, 1940 2,274,341 Mueller Feb. 24, 1942 2,294,579 Sher-man Sept. 1, 1942 2,337,484 McCollum Dec. 21, 1943 2,348,834 Mueller May 16, 1944 2,348,835 Mueller May 16, 1944 2,361,643 Mueller ,Oct. 31, 1944 2,361,644 Mueller Oct. 31, 1944 

